112 resultados para Hernández, José
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Peer-reviewed
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In March of 2004, the Observatory of European Foreign Policy published a special monograph about Spain in Europe (1996-2004) in digital format. The objective of the monograph was to analyse Spain’s foreign policy agenda and strategy during the period of José María Aznar’s presidency. As the title suggests, one of the initial suppositions of the analysis is the Europeanization of Spanish foreign activities. Is that how it was? Did Aznar’s Spain see the world and relate to it through Brussels? The publication was well received, considering the number of visits received and above all the institutions which asked to link the publication to their web pages. Among these, the EUobserver published the introduction to the piece in English titled Aznar: thinking locally, acting in Europe (described by the EUobserver as a paper of utmost importance). The fact that the elections were held three days after the tragic events of the 11th of March dramatically increased interest in Spain and the implications for Europe. This publication is the second of its type, in this case analysing the period of the Zapatero government (2004-2008). Once again the starting premise (the Europeanization of the agenda and the methods employed) has been considered by the analysts. And once again the articles collected in this publication serve to “triangulate” the analysis. Spain and Europe are two vertices (more or less distant, in essence and in form) which the authors handle in their analysis of the case (third vertex).
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En marzo de 2004 el Observatorio de Política Exterior Europea publicó, en versión digital, un monográfico especial sobre España en Europa (1996-2004). Su objetivo era analizar la agenda y la estrategia de España durante el período de José María Aznar en materia de relaciones internacionales. Como bien indicaba el título de aquella publicación, uno de los supuestos de partida del análisis era la europeización de la actividad internacional de España. ¿Era así?, ¿la España de Aznar veía el mundo y se aproximaba a él a través de Bruselas? Aquella publicación tuvo una buena acogida, a la vista de las visitas recibidas y sobre todo de las instituciones que nos pidieron vincular dicha publicación a sus páginas web y, entre ellas, hay que destacar que EUObserver publicó como comentario su artículo introductorio, en versión inglesa, Aznar: thinking locally, acting in Europe (calificado por EUObserver como lectura de máxima relevancia). El hecho de que las elecciones de 2004 se celebraran tres días después de los trágicos acontecimientos del 11-M hizo que el interés por España y por su proyección europea e internacional aumentara de manera destacada. La presente publicación constituye un segundo ejercicio de dicho tipo, en este caso para analizar el período del gobierno Zapatero (2004-2008). Una vez más, el supuesto de partida (la europeización de la agenda y del método) está en la mente de los analistas. Y una vez más los artículos recogidos en esta publicación hacen el ejercicio de “triangular” el análisis. España y Europa son dos vértices (más o menos alejados, en el fondo y en la forma) que los autores manejan en sus análisis de caso (tercer vértice)
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Programa Alfa de la Unión Europea para América Latina. Programa Marco Interuniversitario para la política de equidad y cohesión social en la Educación Superior. Red RIAPE 3. 2011. EuropeAid/129877/C/ACT/Multi
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We have studied domain growth during spinodal decomposition at low temperatures. We have performed a numerical integration of the deterministic time-dependent Ginzburg-Landau equation with a variable, concentration-dependent diffusion coefficient. The form of the pair-correlation function and the structure function are independent of temperature but the dynamics is slower at low temperature. A crossover between interfacial diffusion and bulk diffusion mechanisms is observed in the behavior of the characteristic domain size. This effect is explained theoretically in terms of an equation of motion for the interface.
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We present numerical results of the deterministic Ginzburg-Landau equation with a concentration-dependent diffusion coefficient, for different values of the volume fraction phi of the minority component. The morphology of the domains affects the dynamics of phase separation. The effective growth exponents, but not the scaled functions, are found to be temperature dependent.
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Ginzburg-Landau equations with multiplicative noise are considered, to study the effects of fluctuations in domain growth. The equations are derived from a coarse-grained methodology and expressions for the resulting concentration-dependent diffusion coefficients are proposed. The multiplicative noise gives contributions to the Cahn-Hilliard linear-stability analysis. In particular, it introduces a delay in the domain-growth dynamics.
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We consider stochastic partial differential equations with multiplicative noise. We derive an algorithm for the computer simulation of these equations. The algorithm is applied to study domain growth of a model with a conserved order parameter. The numerical results corroborate previous analytical predictions obtained by linear analysis.
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Front and domain growth of a binary mixture in the presence of a gravitational field is studied. The interplay of bulk- and surface-diffusion mechanisms is analyzed. An equation for the evolution of interfaces is derived from a time-dependent Ginzburg-Landau equation with a concentration-dependent diffusion coefficient. Scaling arguments on this equation give the exponents of a power-law growth. Numerical integrations of the Ginzburg-Landau equation corroborate the theoretical analysis.
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We consider systems described by nonlinear stochastic differential equations with multiplicative noise. We study the relaxation time of the steady-state correlation function as a function of noise parameters. We consider the white- and nonwhite-noise case for a prototype model for which numerical data are available. We discuss the validity of analytical approximation schemes. For the white-noise case we discuss the results of a projector-operator technique. This discussion allows us to give a generalization of the method to the non-white-noise case. Within this generalization, we account for the growth of the relaxation time as a function of the correlation time of the noise. This behavior is traced back to the existence of a non-Markovian term in the equation for the correlation function.
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We have studied the growth of interfaces in driven diffusive systems well below the critical temperature by means of Monte Carlo simulations. We consider the region beyond the linear regime and of large values of the external field which has not been explored before. The simulations support the existence of interfacial traveling waves when asymmetry is introduced in the model, a result previously predicted by a linear-stability analysis. Furthermore, the generalization of the Gibbs-Thomson relation is discussed. The results provide evidence that the external field is a stabilizing effect which can be considered as effectively increasing the surface tension.
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The Swift-Hohenberg equation is studied in the presence of a multiplicative noise. This stochastic equation could describe a situation in which a noise has been superimposed on the temperature gradient between the two plates of a Rayleigh-Bnard cell. A linear stability analysis and numerical simulations show that, in constrast to the additive-noise case, convective structures appear in a regime in which a deterministic analysis predicts a homogeneous solution.
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The dynamics of an interface separating the two coexistent phases of a binary system in the presence of external fluctuations in temperature is studied. An interfacial instability is obtained for an interface that would be stable in the absence of fluctuations or in the presence of internal fluctuations. Analytical stability analysis and numerical simulations are in accordance with an explanation of these effects in terms of a quenchlike instability induced by fluctuations.
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We derive nonlinear diffusion equations and equations containing corrections due to fluctuations for a coarse-grained concentration field. To deal with diffusion coefficients with an explicit dependence on the concentration values, we generalize the Van Kampen method of expansion of the master equation to field variables. We apply these results to the derivation of equations of phase-separation dynamics and interfacial growth instabilities.